Electrical connectors subject to plug and unplug motion often suffer from wear, such as fretting, and increased contact resistance due to atmospherically induced corrosion of the contact caused by humidity, pollutants, and oxidation. In the prior art, microcrystalline waxes are known as contact enhancing compositions. In addition, antioxidant lubricating fluids have been used on electrical connectors to decrease this wear and the corrosion to which they are subject. W. O. Freitag, "Lubricants for Separable Connectors," Proceedings of the Twenty-Second Annual Holm Seminar on Electrical Contacts, Institute of Technology, Il, 1976, discusses a wide variety of natural and synthetic materials such as polyphenyl esters, natural and synthetic hydrocarbons, esters, polyglycols, fluorinated materials, and silicones that are available.
Since most fluid lubricants are insulators, their use can actually serve to minimize or entirely prevent the desired metallic contact, and contact resistance between sliding surfaces may be very high.
In an effort to overcome the deficiencies of lubricants, other materials have been utilized. For example, U.S. Pat. No. 4,178,059 teaches a thin self-adherent layer of soft protective plastic having lubricative properties, such as polytetrafluoroethylene, coated on the screw base of an electric lamp.
Gold plating of contacts or contact points is practiced in the art due to the outstanding electrical properties of gold and its known inertness to corrosion. However, the high cost of this metal has made it desirable to eliminate gold plates contacts.
There remains a need in the art for electrical contact enhancing compositions which can provide a high degree of environmental protection to contacts made of metals such as copper alloys coated with metals such as tin, tin/lead, and silver, and which can provide good electrical performance.
U.S. Pat. No. 4,029,843 discloses a polyanhydride resin prepared by reaction of an alpha-olefin, a dicarboxylic anhydride such as maleic anhydride, and water or an amine or an alcohol, the polymeric resin being useful as a release agent.